A vehicle body structure has been known which suppresses deformation of the body of a vehicle by distributing a collision load, caused by an offset collision between the vehicle and an oncoming vehicle (collision object), to increase the strength of the vehicle body (refer to, for example, Japanese Unexamined Patent Application Publication No. 2003-237636).
FIG. 10 is a schematic plan view of the vehicle body in the vehicle disclosed in Japanese Unexamined Patent Application Publication No. 2003-237636 and illustrates a state where a collision load is applied to the vehicle upon narrow offset collision. FIG. 11 is a side elevational view of essential part on the left of the vehicle disclosed in Japanese Unexamined Patent Application Publication No. 2003-237636 and illustrates a state of a door after narrow offset collision.
Referring to FIG. 10, in the vehicle structure disclosed in Japanese Unexamined Patent Application Publication No. 2003-237636, each diagonal member 500 extending from the front end of a side sill 100 rearwardly and inwardly in a direction along the width of the vehicle (hereinafter, referred to as the “vehicle width direction”) is disposed so as to connect a corner at which the side sill 100 is coupled to an outer side member 200 to a corner at which a floor frame (central member) 300 is coupled to the floor cross member 400.
In this case, the diagonal member 500 prevents the side sill 100 from being inwardly bent under a collision load applied from a front wheel T upon narrow offset collision with a collision object, such as an oncoming vehicle C2.
In the related-art vehicle body structure, if a narrow offset collision occurs such that a collision object, e.g., the oncoming vehicle C2 strikes against a portion outside a front side frame 600 in the vehicle width direction as illustrated in FIG. 10, a collision load F will be applied to the front end of the side sill 100. Even if a load applied to the side sill 100 is reduced by the diagonal member 500, therefore, a large load will be applied to the side sill 100 in a direction in which a frontal collision load is applied. Consequently, the side sill 100 is bent and deformed such that it is compressed by a length L100, like a side sill 100A indicated by an alternate long and two short dashes line in FIG. 10.
In this case, a front pillar 700 coupled to an upper portion of the front end of the side sill 100 is also moved to the rear of the vehicle body in accordance with deformation of the side sill 100 as illustrated in FIG. 11, so that front attachment portions 710, included in the front pillar 700, for a door 800 are moved rearward. Unfortunately, the door 800 may become difficult to open.
In a vehicle equipped with no diagonal members 500 as illustrated in FIG. 10, since the front wheel T enters a vehicle interior while moving rearward, the side sill is bent toward the vehicle interior, like a side sill 100B indicated by another alternate long and two dashes line in FIG. 10, so that the vehicle interior is deformed.